Which is probably part of an explanation how you can end up with this: (the sentence in question is in bold font)
Thousands of students are facing the problem of necessary remediation as they enter college. Roughly one of every three entering a public two- or four-year post-secondary school will have to take at least one remedial course, writes Leanne Italie at the Associated Press.
Doing so dramatically increases the odds that he or she won’t graduate, according to a March report from the nonprofit Alliance for Excellent Education.
You might have thought that taking a remedial education class (assuming you need one) would drastically increase your chances of graduating, because, you know... it's part of the requirements, and fulfilling requirements for graduation tends to increase one's chances of graduating.
Now there's a charitable way to read this sentence. We could take "doing so" to mean "having to take" rather than "taking". So "having to take at least one remedial course" drastically decreases your chances. But that interpretation has a problem. The phrase "doing so" is active, and "having to take" is, semantically if not grammatically, passive; it's the equivalent of "being required to take".
Second, and this is an issue for either interpretation, having to take the class doesn't change anyone's odds. It just helps signal what those odds actually are. So saying that it "increases" the odds of not graduating is just false.